JP2004179933A - Fault detection method of back support plate in picture reading system and image reading system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading system that can detect a fault of a back support plate. <P>SOLUTION: Before reading a business format at the start of an image read system 1, a back support plate 2 is scanned to obtain an image. A normal level of the back support plate 2 can be determined by referring to the obtained image of the plate 2 to a previously set threshold table. When the result is an error level after the determination or a stain, a flow or the like is found on the plate 2, the problem can be solved by cleaning and the like, and smooth management can be realized after the start of the operation. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image reading technique, and more particularly, to a method and an image reading system for detecting a reading error when scanning a form.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an image reading apparatus, for example, an optical character reading apparatus, when a background plate (hereinafter, referred to as a “backing plate”) when a form passes through a subject portion of a reading head has stains or scratches, Problems such as failure to read the form occur. Scratches are caused by the peeling of the paint after long use of the device. If there is a problem such as dirt on the backing plate, cleaning is performed, and if the problem is still not solved, measures such as replacement with a new backing plate have been taken.
[0003]
A black backing plate whose surface is set to black is generally used for this backing plate, but a white backing plate whose surface is set to white is used when the form is extremely thin. For example, when reading a very thin form, if a black backing plate is used, the white backing plate is used to prevent the black plate from being read inaccurately. Is done.
On the other hand, in the image reading apparatus, before reading a document image, a white reference plate for correcting shading distortion caused by the optical system is scanned to obtain white reference data, and the document is scanned based on the white reference data. It is known to perform shading correction of an image (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-9-149251 (page 9)
[Problems to be solved by the invention]
However, the white reference plate described in Patent Document 1 is different from the backing plate described above. The former is a reference plate required for shading correction to correct shading distortion caused by the optical system, whereas the latter is a sheet passing through the subject portion of the reading head regardless of the shading distortion. It is a board of the background.
Conventionally, the business of reading forms has been started, and after a problem has occurred, the cause is investigated.If the result indicates that there is a problem with the backing plate, clean it.If the problem persists, replace it with a new one. There was a problem that the business was temporarily interrupted because of the measures such as the above.
[0005]
Therefore, the present invention has been made in view of the above circumstances, and scans a backing plate before starting a business to solve a problem of a form reading error that may occur, and to smoothly execute a business after a business starts. It is an object of the present invention to provide an image reading apparatus capable of performing various operations.
[0006]
[Means for Solving the Problems]
In order to solve these problems, an abnormality detection method for a backing plate in an image reading apparatus according to the present invention includes an image reading apparatus for acquiring an image of a recording medium passing over the backing plate, and It is characterized by comprising an acquiring step of acquiring and a determining step of determining a state of the backing plate based on the image of the backing plate acquired by the acquiring step.
The determining step in the method for detecting an abnormality of the backing plate in the image reading apparatus of the present invention compares the acquired image of the backing plate with reference data for determining the state of the backing plate. It is also characterized by judging the state.
[0007]
Further, the reference data in the method for detecting an abnormality of a backing plate in the image reading apparatus of the present invention is data indicating whether the state of the backing plate is a normal state, a warning state, or an error state. .
Next, the image reading system according to the present invention is an image reading system for acquiring an image of a recording medium passing over a backing plate, wherein: an acquiring unit for acquiring an image of the backing plate; and a backing acquired by the acquiring unit. Determining means for determining the state of the backing plate based on the image of the plate.
[0008]
Further, the image reading system of the present invention further comprises reference data holding means for holding reference data for judging the state of the backing plate, wherein the judging means comprises an acquired image of the backing plate and the reference data holding means. The state of the backing plate is determined by comparing the stored reference data.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, an outline of the image reading apparatus of the present invention will be described with reference to FIG.
FIG. 1 is a diagram illustrating the configuration of the optical character reading device 1. The backing plate 2 is a background plate through which a form passes in the subject portion of the CCD 8. The hopper 3 is a place where the forms to be read are stacked and set, and the forms stacked on the hopper 3 are taken into the apparatus by the feed roller 4. Further, in order to prevent two or more forms from being fed at one time, the double feed for feeding a plurality of sheets is prevented by rotating the separator 5 in reverse with respect to the feed roller 4.
[0010]
The light source lamp 6 irradiates light onto the backing plate 2. When the form passes over the backing plate 2, reflected light of the form with respect to light emitted from the light source lamp 6 is received by the CCD 8 through the lens 7, and a form image 18 is obtained. The transport path 9 is a path on which the form is transported, and the form is transported by the transport rollers 10.
If the form is successfully read, the form is separated by the select gate 11 and discharged to the accept stacker 12 and stored. On the other hand, when the reading of the form fails, or when the form is erroneously detected, the form is sorted by the select gate 11 and discharged to the reject stacker 13 and stored.
[0011]
Next, an example of passing a form when the backing plate is dirty and an example of an image thereof will be described with reference to FIGS.
FIG. 2 shows the state immediately before the form 16 passes in the direction of the arrow on the CCD scanning line 15 existing on the backing plate 2 when the backing plate 2 has dirt 14. On the other hand, FIG. 3 shows an example of an image of the form 16 obtained by passing over the CCD scanning line 15 under the situation of FIG. The backing plate 2 of FIG. 2 corresponds to the backing plate image 17 of FIG. 3, the dirt 14 of FIG. 2 corresponds to the dirt image 19 of FIG. 3, and the form 16 is obtained corresponding to the form image 18. . Each image can be represented by a black and white binary image. For example, the color tone of the image shown in FIG. 2 or FIG. 3 is represented by the reflected light level with respect to the light received from the light source lamp 6 when the form 16 passes over the CCD scanning line 15, and the stain 14 has the reflected light level. High, as shown in FIG.
[0012]
In the optical character reading device, the image shown in FIG. 3 is searched, and only the portion of the form image 18 is extracted and the image is read or the characters written in the form 16 are read. If there is a stain 14 or the like, the stain image 19 may be erroneously detected as the form image 18. Further, depending on the size of the dirt 14 or the position of the dirt 14, the form image 18 may be affected. For example, in FIG. 2, when the dirt 14 is present on the passage of the form 16, the dirt image 19 overlaps with the form image 18, and the optical character reading device 1 accurately detects the leading end of the form image 18. You can't do that.
[0013]
Next, the operation of the present invention will be described with reference to FIG. 4, FIG. 5, FIG. 6, and FIG. As a specific example of the operation of the present invention, it is assumed that the backing plate 2 has dirt 14.
FIG. 4 is a flowchart for explaining the operation of the embodiment of the present invention. Hereinafter, the operation of the optical character reading device 1 of the present invention will be described with reference to this flowchart. This flowchart is realized by the operation of a personal computer (not shown) connected to the optical character reading device 1 and having a control application program installed.
[0014]
FIG. 5 shows an image of the backing plate 2 obtained by scanning the backing plate 2 having the stain 14 when starting up the optical character reading apparatus 1.
FIG. 6 is a specific example showing the level of the reflected light with respect to the light received by the backing plate 2 from the light source lamp 6 when the backing plate 2 is scanned. The maximum value in FIG. 6 is 255, at which time the image is white. On the other hand, the minimum value in FIG. 6 is 0, and the image is black at this time. Although the position of the horizontal axis in FIG. 6 represents the position of the backing plate, it is actually represented by the position of the pixel of the CCD scanning line 15. Further, the threshold value is a predetermined value, and may be set by an administrator. For example, the threshold is set to 128.
[0015]
FIG. 7 shows a warning error determination threshold value table. The state of the backing plate image 20 is a normal level indicating a state in which the optical character reading device 1 can accurately read the image, and there is no problem in reading the image. A warning level is a level that indicates a state that is good, and an error level is a level that indicates that it is extremely difficult or impossible to read accurately.
[0016]
When the reflected light level in FIG. 6 exceeds a predetermined threshold line (threshold = 128), if the width is four pixels in a row, it is determined as an error. If there are 1 to 3 pixels in a row, it is determined as a warning level, and if there are 0 pixels, it is determined as a normal level. Even if they are not continuous, if the number of pixels exceeding the threshold value (= 128) on the CCD scanning line 15 is cumulatively 100 pixels or more, an error level is obtained. It is determined as a normal level.
[0017]
First, the power of the optical character reader 1 is turned on. After turning on the power, a start-up process is started (S1). Specifically, an initialization process for a volatile memory such as a buffer or a register existing in a control unit (not shown) inside the optical character reading device 1 is executed. Thereafter, the backing plate image 20 is obtained (S2). The backing plate image 20 is obtained by scanning the same portion of the backing plate 2 many times and connecting the images obtained in time series. When the backing plate image 20 is obtained, this image is compared with the warning error determination threshold value table shown in FIG. 7 and checked (S3).
[0018]
Next, the state of the backing plate image 20 is determined based on the result of S3 (S4). This determination is divided into the normal level, the warning level, and the error level as described above.
First, when it is determined that the state of the backing plate image 2 is at the normal level, the startup processing of the optical character reading device 1 ends normally (S5). Next, when it is determined to be at the warning level, the optical character reading device 1 outputs a warning message to a display of a personal computer connected to control the optical character reading device 1 (S6). Then, the start-up process ends normally (S5). Further, when it is determined that the error level is at the error level, the optical character reading device 1 outputs an error message to a display of a personal computer connected to control the optical character reading device 1 (S7), The start-up process does not end normally and ends as an error (S8), and the optical character reader 1 cannot be operated.
[0019]
By the above processing, by scanning the backing plate 2 before starting the work, it is possible to know the presence of dirt, scratches and the like on the backing plate 2.
As described above, according to the embodiment of the present invention, when the optical character reader 1 is started up, the backing plate image 20 obtained by scanning the backing plate 2 is set to the predetermined warning error threshold value. The state of the backing plate 2 can be determined by referring to the table. As a result of the determination, when the error level is attained, the presence of dirt or scratches on the backing plate 2 is recognized. At this time, the problem can be solved by cleaning or the like, and smooth operation can be performed after the start of work.
[0020]
The present invention is not limited to the above-described embodiment, and can be implemented with various modifications without departing from the spirit of the invention. For example, for a scratch or abrasion caused by long-term use of the device, a warning is issued when the scratch or abrasion reaches a certain level. For example, replacement during the next periodic inspection will enable smooth operations.
In the embodiment of the present invention, the backing plate is black and the dirt is white, but the backing plate may be of any color such as dirt or scratch.
[0021]
【The invention's effect】
When the image reading apparatus is started up, the state of the backing plate can be determined by referring to the backing plate image acquired by scanning the backing plate with reference to a preset warning error threshold table. As a result of the determination, when the error level is attained, the presence of dirt or scratches on the backing plate is recognized. At this time, the problem can be solved by cleaning or the like, and smooth operation can be performed after the start of work.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of an optical character reading device.
FIG. 2 is a diagram illustrating a state immediately before a form passes when a backing plate is dirty.
FIG. 3 is an image of a form, a backing plate, and a stain in the embodiment of the present invention.
FIG. 4 is a flowchart illustrating an operation of the exemplary embodiment of the present invention.
FIG. 5 is an image of a backing plate obtained by scanning a backing plate having a stain when the optical character reading device is started up.
FIG. 6 is a diagram showing the level of reflected light with respect to the light received by the backing plate from the light source lamp when scanning the backing plate with respect to the position of the backing plate.
FIG. 7 is a warning error determination threshold value table serving as an index indicating the state of the backing plate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image reading device 2 ... Backing plate 3 ... Hopper 4 ... Feeder 5 ... Separator 6 ... Light source lamp 7 ... Lens 8 ... CCD board 9 ... Conveying path 10 Conveying roller 11 Select gate 12 Accept stacker 13 Reject stacker 14 Dirt 15 CCD scanning line 16 Form 17, 20 Back Backing plate image 18 ... Form images 19, 21 ... Dirt image

Claims (5)

In an image reading device that acquires an image of a recording medium passing over a backing plate,
An obtaining step of obtaining an image of the backing plate,
Determining a state of the backing plate based on the image of the backing plate acquired in the acquiring step. The method according to claim 1, wherein the determining step determines the state of the backing plate by comparing the acquired image of the backing plate with reference data for determining the state of the backing plate. An abnormality detection method for a backing plate in an image reading device. The abnormality detection of the backing plate in the image reading device according to claim 2, wherein the reference data is data indicating whether the state of the backing plate is a normal state, a warning state, or an error state. Method. In an image reading device that acquires an image of a recording medium passing over a backing plate,
Acquisition means for acquiring an image of the backing plate;
An image reading system comprising: a determination unit configured to determine a state of the backing plate based on the image of the backing plate acquired by the acquisition unit. Further comprising reference data holding means for holding reference data for determining the state of the backing plate,
The method according to claim 4, wherein the determining unit determines the state of the backing plate by comparing the acquired state of the backing plate with the reference data held by the reference data holding unit. Image reading system.

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